Mobo Capacitor Resistance

[GSTARR]

Hey guys,

 

With everything powered off and unplugged - what resistance should I expect on good capacitors?

 

Im reading (on the 20K setting on my multimeter):

 

1) multiple at~0.2-0.6 (I stopped testing them at that point) and they were increasing by 0.05

 

2) A couple that were still in that range, but only increasing by 0.01

 

3) A couple that jumped into 6.xx and 7.xx and then only increased by .01 after that

 

If it depends on the motherboard, what is the name of the layout, what specs should I be looking for?

[mariushm]

You can't do such tests with a multimeter on a motherboard.

 

Multimeter uses a low current to measure resistance, that low current would simply charge up the capacitor and you don't get a meaningful value.

Also, on motherboards capacitors are often installed in parallel, or they're in series with inductors or other components that will affect the measurements.

 

Either way, resistance measurement doesn't tell you anything about a capacitor being good or bad. On electrolytic capacitors, you need to measure the ESR, and you can't measure ESR with regular multimeters because ESR must be measured with an AC signal. You would need an ESR meter or a LCR meter with ESR function.

 

 

[Kilrah]

1 hour ago, mariushm said:

You would need an ESR meter or a LCR meter with ESR function.

And actually disconnect the capacitor from the circuit of course.

[GSTARR]

On 10/1/2023 at 3:54 PM, Kilrah said:

And actually disconnect the capacitor from the circuit of course.

@mariushm

 

thanks guys!

 

I suppose then that I wont be doing this anytime soon. I'm hoping in the next year or two I'll be able to comfortably afford tools to fix this guy, or at the very least learn how to properly diagnose the situation and declare it beyond me with 100% certainty.